faulty battery?

[jimmydoc]

Hi, my ebike was on charge as usual last night, but today nothing is working. I removed the battery ( Hailong 48 volt 13 Ah) and checked the power output, it's reading 49 volts. When I press the power indicator button, the lights quickly flash and don't stay on. No 5 volt power coming from the built in USB either.
I plugged in the charger (battery off the bike), and checked the voltage, it's showing 90 volts !! I double checked the reading with another Multimeter, same result.
I connected a fully charged 36 volt battery to the bike, still nothing working. Hailong battery is 9 months old. Is the battery faulty and could that heavy voltage have goosed my motor? Thanks for any advice.

 

[Nealh]

Replace the meter battery with a new one and check again.
A 48v battery can't attain 90v so something is giveing an eronuos reading.
Check the charger output only to see if it is wrong.
The original 49v mentioned is low so something is amiss.

 

[jimmydoc]

The charger is showing an output of approx. 85 volts, my meters are obviously ok., the high voltage appears to be going straight through the battery when the charger is plugged into the mains.
There's also a slight pungent smell from the battery when it's plugged into the charger. I think I should just return it

 

[cyclebuddy]

If the charger is outputting 85+ volts, I'd be pretty sure you're going to find it's the isolation on the secondary winding has failed and is passing high voltage from the primary through to the output/battery. It happens from time-to-time with cheap switch-mode power supplies/chargers.

It won't be a good outcome for anything connected to it...

 

[jimmydoc]

Thanks for your help, I'll return them . Do you think my Bafang motor will be damaged? Can motors be repaired?

 

[Nealh]

The BMS has likely fried then, it is battery specific depending on voltage and certainly won't handle the higher voltage not intended to be seen. The bms will use a voltage regulator or mosfets for switching so these and other pcb parts may be damaged.
It is a warranty claim.
The hub should be fine but the controller will likely be toast as well or at least the inrush capacitor, it will have a 63v rating.

 

[sjpt]

Thanks for your help, I'll return them . Do you think my Bafang motor will be damaged? Can motors be repaired?

I think it unlikely the motor will have been damaged. The battery may well have been. You are probably quite lucky not to have had a major fire.

If the battery and charger came together and they are still under warranty the supplier should replace both.

 

[Nealh]

One reason why I check my chargers before connecting for charging, two seconds to make sure output voltage is as it should be.

 

[jimmydoc]

Thanks to all for your advice, I'll contact the supplier